<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<button id="bt1">ok</button>
	</body>
	<script>
	var bt1=document.getElementById("bt1");
	bt1.onmousedown=function(){
		console.log(arguments[0])
	}
	
	
	</script>
</html>
